1. Field of the Invention
This invention relates to a critical wind direction indicator.
More particularly, the invention relates to an indicator of the type which shows the direction of the wind at extremely low wind velocity as well as at high velocity. It is particularly useful in areas likely to be invaded by toxic gas, for example, H.sub.2 S, as a warning to people to vacate these areas. This is a common problem in the oil fields of Western Canada.